Posted
by
ScuttleMonkey
on Monday February 08, 2010 @07:05PM
from the size-does-matter dept.

natharward writes "A new development in nano-level diagnostic tests has been applied as a lab on a chip that successfully screened viruses entirely by their size. The chip's traps are size-specific, which means even tiny concentrations of viruses or other particles won't escape detection. For medicine, this development is promising for future lab diagnostics that could detect viruses before symptoms kick in and damage begins, well ahead of when traditional lab tests are able to catch them. Aaron Hawkins, the BYU professor leading the work, says his team is now gearing up to make chips with multiple, progressively smaller slots, so that a single sample can be used to screen for particles of varying sizes. One could fairly simply determine which proteins or viruses are present based on which walls have particles stacked against them. After this is developed, Hawkins says, 'If we decided to make these things in high volume, I think within a year it could be ready.'"

Comparisons between humanity and viruses might be fun in the Matrix and the like, but it is a really bad analogies. We're quite standard as mammals go. Agent Smith says in the Matrix:

"I'd like to share a revelation that I've had, during my time here. It came to me when I tried to classify your species and I realized that you aren't actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with its surrounding environment, but you humans do not. You move to an area and you multiply, and multiply until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we... are the cure."

But this is ridiculous. Lot's of species do exactly this. It is quite difficult for species of any sort not to keep expanding until all resources are consumed, since each individual has an evolutionary incentive to do so. In fact, viruses and many other parasitical organisms are in some respects more restrained in some ways co

Well, if you insist on an answer: only an 'idiot' wouldn't know that a virus is much, much smaller than a human cell, and since the device from TFA identifies viruses by size (among other things) they wouldn't identify humans (or any other animal) as a virus.

Probably. 'Evolution' for viruses involve swapping or mutating a few base pairs. So I imagine the overall size/structure won't change much. I'd say the tricky part is not detecting a virus after it's mutated but in discerning a virus from molecules of a similar size and polarity.

Maybe this was a troll, but I'll respond anyway.
Members of the Church of Jesus Christ of Latter Day Saints (aka Mormons) do believe that God created the Earth. Which is "creationism".
However most LDS folks also believe in evolution (e.g. as part of God's creation) and BYU was one of the very first schools to teach evolution. Last year BYU had a big, well-publicized week-long celebration of Darwin's birthday that included many lectures on the importance of the discovery of evolution.

Maybe this was a troll, but I'll respond anyway. Members of the Church of Jesus Christ of Latter Day Saints (aka Mormons) do believe that God created the Earth. Which is "creationism". However most LDS folks also believe in evolution (e.g. as part of God's creation) and BYU was one of the very first schools to teach evolution. Last year BYU had a big, well-publicized week-long celebration of Darwin's birthday that included many lectures on the importance of the discovery of evolution.

*shrug* Once you believe in a supernatural, one set of beliefs isn't particularly more wacky than the next, just more or less familiar.

Wrong. There's a big difference, to me, between beliefs which cannot be proven or disproven, and beliefs which are blatantly disproven by available physical evidence. If someone believes that a "god" lives on some other planet, ok, that sounds pretty wacky to me, but there's no way for me to disprove that, at least not now when we have no manned spaceflight and certainly n

Wrong. There's a big difference, to me, between beliefs which cannot be proven or disproven, and beliefs which are blatantly disproven by available physical evidence.

Yes and no - I agree that if I had to choose between the two I would choose the former, but both are products of poor reasoning. If the only rational defence someone has of their viewpoint is that it has not been disproven than I can't really respect that kind of reasoning.

Your examples of insane excuses are also things that cannot be proven - yet you dismiss these, while partially defending equitable (from a rational point of view) views about gods that live on other planets, talking to people etc. Thi

Any biblical religion believes what the bible said, scooping Darwin by at least 5,000 years: "[Animals] were made fruitful and able to multiply -- in the sea and on the earth -- each after its own kind."

ID is not an excuse to teach creationism, as thought up by clever bible-thumpers. It is merely a heresy, crafted by perverting religion to meet a perverted science. It should be treated as such, and not used as a reason to hate anything but ID. Mormonism, as a religion, rejects ID. You might find a few

My wife keeps telling me that size doesn't matter... how then can viruses be identified solely by their size? It's not how big the molecules are that are important, it's what the virus can do with them!

It is amazing how technologies shown in Star Trek 45-15 years ago (esp TNG, and Voyager if I daresay) have brought to life by scientists who were inspired by its intellectual dialogue and its incredible technology. Many of the things Star Trek did...like teleporters and replicators, phasers and tricorders, and pads, we marvel at and sometimes wonder how they ever possibly could work, a seemingly impossible feat of mankind's ingenuity. And yet, over the years we have seen so many of them come to life; the Kindle and the iPAD awe me every time I see them. Consider also, MRI imaging. The ability to bring a momentarily-dead person back to life. Transplants of major organs and body parts. And now, possibly, the ability to measure the some of the most minute details of a human that we could possibly conceive. Is this another incredible step forward for mankind and his unrelenting technological, intellectual aspirations? I can't wait to see.

The medical technology shown on BSG was really rather primitive, compared to what you'd expect for a civilization that's had interstellar spaceflight for 2000 years and also had FTL drive and artificial gravity. Their sickbay didn't look much more advanced than what we currently have; I believe they even had what appeared to be a simple MRI machine, which the Dr. used to examine Baltar's head.

Not to mention the gap in the detector is smaller than plant and animal cells entirely:

They formed the third dimension by placing a 50 nanometer-thin layer of metal onto the chip, then topping that with glass deposited by gasses. Finally they used an acid to wash away the thin metal, leaving the narrow gap in the glass as a virus trap.

DNA microarrays (also know as DNA chips) can already identify every virus ever discovered, and it can even identify undiscovered viruses by recognizing genetic sequences that are highly conserved among viruses. This type of chip first proved its worth in 2003 when it was used to identify SARS. The New York Times interviewed the inventor Joseph DeRisi about it [nytimes.com]:

We had just finished building the full version of our ViroChip, when we read about SARS in the newspapers. We literarily begged the C.D.C. to send us samples of the virus. Once we had it, we immediately put it onto a chip. In less than 24 hours we confirmed that this was a novel coronavirus. We confirmed the ViroChip’s finding by subsequently sequencing this virus’s genome. This had never in history happened before.

It is not yet evident what, if any, advantage this other chip that hopes to identify viruses by their size will have.

Microarrays are expensive. The technology requires quite a few steps, so affymetrix chips are amazingly cheap all things considered.
This technology is a glass sieve.. modern technology can do this cheaply at scale.
The awesome factor is that a raman spectrometer could probably be used to nail down some of the ambiguities for similar sized proteins. As a thin glass layer will be transparent, and the samples are in predefined locations. Since youve got to optically scan the sample anyway, why not get a raman read in the process.
And the data analysis is much more straightforward.. with a genechip, you look for a specific pattern, which may be weird if you have viruses in a sample. Where size sorting gets single on-off data points which indicate a virus of size-x which will correspond to one (possibly more) viruses.. it narrows the search pretty fast if you have yes-no answers. Plus you can do a targeted microarray when you have a narrow search field. But most of the time - sorting cold from flu from ebola and hiv is enough.
I kinda suspect that this might be pretty quick to run, as the virus only needs to move a minute (.005-.5mm-ish id supose) amount, and an ultracentrifuge can make short work of sorting much larger samples that need to separate proteins by a few millimeters. But hey, what do I know?
Storm

Ok, so I read the article--unsurprisingly it was light on the details. The sieve idea is good, but a few questions come to mind,

1) How are you going to do the actual virus identification? Most of the current techniques require an amplification step because you need enough signal to measure. It is great to be able to isolate small amounts, but not if you can't do anything with it. Morphological identification is one way to go, but you can only get species information that way (sometimes). You can't get strai